1 //! Implementation of panics via stack unwinding
3 //! This crate is an implementation of panics in Rust using "most native" stack
4 //! unwinding mechanism of the platform this is being compiled for. This
5 //! essentially gets categorized into three buckets currently:
7 //! 1. MSVC targets use SEH in the `seh.rs` file.
8 //! 2. Emscripten uses C++ exceptions in the `emcc.rs` file.
9 //! 3. All other targets use libunwind/libgcc in the `gcc.rs` file.
11 //! More documentation about each implementation can be found in the respective
15 #![unstable(feature = "panic_unwind", issue = "32837")]
16 #![doc(issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/")]
17 #![feature(core_intrinsics)]
18 #![feature(lang_items)]
20 #![feature(panic_unwind)]
21 #![feature(staged_api)]
22 #![feature(std_internals)]
23 #![feature(unwind_attributes)]
24 #![feature(abi_thiscall)]
25 #![feature(rustc_attrs)]
28 #![feature(panic_runtime)]
29 // `real_imp` is unused with Miri, so silence warnings.
30 #![cfg_attr(miri, allow(dead_code))]
32 use alloc::boxed::Box;
34 use core::panic::BoxMeUp;
37 if #[cfg(target_os = "emscripten")] {
40 } else if #[cfg(target_os = "hermit")] {
43 } else if #[cfg(target_env = "msvc")] {
47 all(target_family = "windows", target_env = "gnu"),
49 target_family = "unix",
50 all(target_vendor = "fortanix", target_env = "sgx"),
52 // Rust runtime's startup objects depend on these symbols, so make them public.
53 #[cfg(all(target_os="windows", target_arch = "x86", target_env="gnu"))]
54 pub use real_imp::eh_frame_registry::*;
58 // Targets that don't support unwinding.
60 // - os=none ("bare metal" targets)
62 // - nvptx64-nvidia-cuda
71 // Use the Miri runtime.
72 // We still need to also load the normal runtime above, as rustc expects certain lang
73 // items from there to be defined.
77 // Use the real runtime.
83 /// Handler in libstd called when a panic object is dropped outside of
85 fn __rust_drop_panic() -> !;
87 /// Handler in libstd called when a foreign exception is caught.
88 fn __rust_foreign_exception() -> !;
93 #[rustc_std_internal_symbol]
94 #[allow(improper_ctypes_definitions)]
95 pub unsafe extern "C" fn __rust_panic_cleanup(payload: *mut u8) -> *mut (dyn Any + Send + 'static) {
96 Box::into_raw(imp::cleanup(payload))
99 // Entry point for raising an exception, just delegates to the platform-specific
101 #[rustc_std_internal_symbol]
103 pub unsafe extern "C" fn __rust_start_panic(payload: *mut &mut dyn BoxMeUp) -> u32 {
104 let payload = Box::from_raw((*payload).take_box());